This application is the national phase of international application PCT/JP96/03608 filed Dec. 11, 1996 which designated the U.S.
1. Field of the Invention
This invention relates to a copy control method and copy control apparatus applied to a data processing system having the function of reproducing and outputting data, such as movies or music, compressed by, for example, the MPEG 2 standard. Such data is referred to herein as xe2x80x9cprovided data.xe2x80x9d
The present invention relates to a copy control method and copy control apparatus which, when recording and reproducing the data recorded on a large capacity recording medium, such as a CD-ROM or a DVD (digital video disk), as copied data, enables the reproduction of the copied data to be controlled by the specific control information recorded on the medium.
The present invention relates to a method of and apparatus for controlling the copying of data supplied by communicating through a computer system having the function of receiving provided data, such as movies or music, via communication means and reproducing and outputting the provided data.
2. Description of Related Art
For systems that reproduce and output data supplied from the film industry or the music industry, compressed by the MPEG 2 standard, copy protection techniques are required to prevent unauthorized copying.
When providing data by computer systems that reproduce and output the data, it is essential to establish highly reliable copy protection techniques capable of preventing unauthorized copying. These copy protection techniques must not be capable of being broken by computer processing.
With conventional copy protection techniques of this type, copy protection data is also recorded on a recording medium, such as a CD-ROM on which the provided data has been recorded, and the copy protection data, together with the provided data, is read and transferred to a copy protection unit, which performs a copy protection process on the provided data, thereby preventing unauthorized copying.
In conventional copy protection techniques, however, the copy protection process is not carried out until the provided data recorded on the disk has been transferred to the copy protection unit. This permits intentional unauthorized copying of the provided data in a system configurations having a computer acting as a transfer unit between the disk reading unit and reproducing unit.
As described above, with a conventional system where the provided data is exchanged via a computer, a highly reliable copy protection technique capable of preventing unauthorized copying has not been established. When a computer system is used that enables part of the provided data to be selectively read into the computer and used this leads to the problem of permitting the unauthorized copying of all of the provided data.
It is, an object of the present invention to overcome the disadvantages in the prior art by providing a highly reliable copy control method and copy control apparatus that reliably prevents unauthorized copying even when a computer intervenes in the exchange of data supplied from a large capacity recording medium, or the like (the xe2x80x9cmediumxe2x80x9d).
Furthermore, it is an object of the present invention to provide a highly reliable copy control method and copy control apparatus that enable the medium to control copying ability arbitrarily on a provided data basis without showing key data used in enciphering and deciphering to a computer that intervenes in the exchange of data supplied from a medium. Such a copy control method and apparatus will always enable the use of the provided data through authorized copying.
In an embodiment of the present invention, when a device capable of copying, such as a computer, intervenes in the exchange of data supplied from a medium, the data read from the medium is enciphered by a specific key on the computer. It is then possible to control a decision as to whether to reproduce the copied data arbitrarily.
Furthermore, according to an embodiment of the present invention, a highly reliable copy control method and copy control apparatus enables a side having the medium to control reproduction of the copied data arbitrarily on a provided data basis without showing the key data used in enciphering and deciphering to a computer that intervenes in the exchange of data supplied from a medium. The copying control method and apparatus always enable the use of the provided data through authorized copying.
In an embodiment of the present invention, the action of recording the data supplied from the medium in a storage device, and reading and reproducing the recorded data is referred to as reproduction of the copied data.
Specifically, an embodiment of the present invention comprises, in a system provided with a drive for reading the data recorded on a large capacity recording medium, a data reproducing device for receiving the data read by the drive via data transfer means, reproducing the received data, and outputting the reproduced data, and means for recording the data transferred from the data transfer means as copied data. The data sent from the drive to the data transfer means is enciphered using the key data generated by the data reproducing device. Only the data reproducing device has the key data used in enciphering and is allowed to reproduce the copied data (i.e., is allowed to make a first generation copy).
Furthermore, an embodiment of the present invention comprises, in the above system, the drive and the data reproducing device each generating mutually related key data separately on the basis of random numbers, the drive enciphering the data to be outputted to the data transfer means using its self-generated key data, and the data reproducing device deciphering the data received from the data transfer means using its self-generated secondary key data, thereby permitting only the data reproducing device having the related key data to perform reproduction without giving to the data transfer means the key data used in enciphering and deciphering and disabling the reproduction of the copied data.
Furthermore, an embodiment of the present invention comprises, in the system, the drive and the data reproducing device recognizing the copy permission level on the basis of the specific control data recorded on the large capacity recording medium. When the recognized level is the level permitting the copied data to be reproduced, the data read by the drive is given to the data transfer means without enciphering. When the recognized level is the level permitting only a specific data reproducing device to reproduce the copied data, the data read by the drive is enciphered using the key data generated by the data reproducing device that is to perform reproduction and the enciphered data is given to the data transfer. When the recognized level is the level inhibiting the reproduction of the copied data, the drive and the data reproducing device temporarily generate mutually related key data using random numbers, thereby enabling only the data reproducing device having the related key data to reproduce the data read by the drive and disabling all of the data reproducing devices including one having the related key data from reproducing the copied data.
Furthermore, an embodiment of the present invention comprises, in a system including a data providing device for providing data via communication means, a data reproducing device for receiving data from the data providing device via the communication means, reproducing the received data, and outputting the reproduced data, and means for recording the data provided to the data reproducing device via the communication means as copied data. The data providing device receives key data from the data reproducing device and on the basis of the key data, enciphers the data to be given to the data reproducing device, thereby enabling only the data reproducing device having the key data used in enciphering to reproduce the copied data.
Furthermore, an embodiment of the present invention comprises, in the above system, the data providing device and the data reproducing device generating mutually related key data separately using random data, the data providing device enciphering the data to be sent to the data reproducing device using its self-generated enciphering key data, and the data reproducing device deciphering the data received from the data providing device using its self-generated deciphering key data, thereby enabling the data received via the communication means to be reproduced and disabling the copied data from being reproduced.
Furthermore, an embodiment of the present invention comprises, in the system, the data providing device sending copy permission data specifying the permission level of copied data to the data reproducing device, and the data reproducing device recognizing the permission level of the copy of the provided data on the basis of the copy permission data received from the data providing device. When the recognized level is the permission level enabling the copied data to be reproduced, the data to be provided is given without enciphering to the data reproducing device via the communication means. When the recognized level is the permission level enabling only a specific data reproducing device to reproduce the copied data, the key data is received from the data reproducing device and the provided data enciphered on the basis of the key data is given to the data reproducing device via the communication means, and when the recognized level is the permission level inhibiting the copied data from being reproduced, the data providing device and the data reproducing device temporarily generate mutually related key data using random data, and the provided data enciphered on the basis of the key data is given to the data reproducing device via the communication means.
With the aforementioned copy control mechanisms, even in a system where a device capable of copying, such as a computer, intervenes in the exchange of the data supplied by a large capacity recording medium, a communication medium, or the like, it is possible to construct a highly reliable system which enables the medium side to control the reproduction of the copied data on the provided data basis without showing the key data used in enciphering and deciphering to an intervening computer, and which always enables the provided data to be used in the form of an authorized copy.